Advice:
When you start a new post or page, add the title, set it to private and then publish it. When you are done, set it back to publish and update it. Another option is to get and use an offline blog client such as Windows Live Writer (Windows) or Ecto (Mac) and then everything is saved on your computer and when you are done with the post, you actually publish it directly from the blog client software. See here for offline blog editors so you don't have to go through this again http://en.support.wordpress.com/xml-rpc